getresuid, getresgid - get real, effective, and saved user/group IDs
#define _GNU_SOURCE /* See feature_test_macros(7) */
#include <unistd.h>
int getresuid(uid_t *ruid, uid_t *euid, uid_t *suid);
int getresgid(gid_t *rgid, gid_t *egid, gid_t *sgid);
getresuid() returns the real UID, the effective UID, and the saved
set-user-ID of the calling process, in the arguments ruid, euid,
and suid, respectively. getresgid() performs the analogous task
for the process's group IDs.
On success, zero is returned. On error, -1 is returned, and errno is set
to indicate the error.
- EFAULT
- One of the arguments specified an address outside the calling program's
address space.
These system calls appeared on Linux starting with kernel 2.1.44.
The prototypes are given by glibc since version 2.3.2, provided
_GNU_SOURCE is defined.
These calls are nonstandard; they also appear on HP-UX and some of the BSDs.
The original Linux getresuid() and getresgid() system calls
supported only 16-bit user and group IDs. Subsequently, Linux 2.4 added
getresuid32() and getresgid32(), supporting 32-bit IDs. The
glibc getresuid() and getresgid() wrapper functions
transparently deal with the variations across kernel versions.
This page is part of release 5.11 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the latest
version of this page, can be found at https://www.kernel.org/doc/man-pages/.